Cor Pulmonale

ℹ️ About

• Cor Pulmonale refers to right ventricular enlargement and right ventricular failure due to primary pulmonary disease or hypoxia.
• It results from increased resistance in the pulmonary circulation, leading to strain on the right side of the heart.

🧬 Aetiology

• Hypoxia acts as a vasoconstrictor in the pulmonary vasculature, leading to increased pulmonary artery pressure and strain on the right ventricle.
• Chronic hypoxia and resultant pulmonary hypertension are the primary mechanisms driving cor pulmonale.

Causes

• Chronic Obstructive Pulmonary Disease (COPD): The most common cause of cor pulmonale, due to chronic hypoxia and airflow obstruction.
• Primary Pulmonary Hypertension: Elevated pressures in the pulmonary arteries, often idiopathic.
• Recurrent Pulmonary Emboli: Causes increased resistance in the pulmonary circulation.
• Sickle Cell Disease: Chronic hemolysis and vaso-occlusion can lead to pulmonary hypertension.
• Bronchiectasis: Chronic infection and inflammation cause pulmonary vascular changes.
• Interstitial Lung Disease (ILD): Chronic inflammation and scarring lead to increased resistance in the pulmonary vasculature.
• Cystic Fibrosis: Persistent lung infections and scarring increase pulmonary pressures.
• Ankylosing Spondylitis: Associated with restrictive lung disease and chest wall rigidity, increasing the risk of cor pulmonale.
• Hypoventilation Syndromes: Conditions like obesity hypoventilation syndrome (OHS) lead to chronic hypoxia and pulmonary hypertension.

🩺 Clinical Features

• Symptoms:
  • Progressive dyspnoea, especially on exertion.
  • Fatigue and syncope due to reduced cardiac output.
  • Leg oedema and ascites from systemic venous congestion.
  • Orthopnoea and paroxysmal nocturnal dyspnoea (PND) in advanced cases.
• Signs:
  • Elevated jugular venous pressure (JVP) with a prominent "a" wave.
  • Loud second heart sound (P2) due to increased pulmonary pressures.
  • Right ventricular heave or parasternal heave.
  • Right-sided third heart sound (RV S3) indicating right ventricular dysfunction.
  • Hepatomegaly and possible liver pulsations due to right heart failure.

🔎 Investigations

• Blood Tests:
  • Full Blood Count (FBC): May show polycythaemia secondary to chronic hypoxia.
  • Arterial Blood Gases (ABGs): Show hypoxia and possibly hypercapnia, indicating chronic respiratory insufficiency.
• ECG:
  • Shows signs of right heart strain such as right ventricular hypertrophy (RVH), right axis deviation (RAD), and P pulmonale (tall peaked P waves).
  • Atrial fibrillation may be present in advanced disease.
• Chest X-ray (CXR):
  • May show a prominent pulmonary artery, right ventricular enlargement, and evidence of underlying lung disease.
• Echocardiography:
  • Assesses right ventricular size and function, pulmonary artery pressures, and can help confirm the diagnosis.
• Ultrasound of Abdomen: May show hepatomegaly and signs of liver congestion due to right heart failure.

💊 Management

• General Measures:
  • Avoid further hypoxic stress by ensuring adequate oxygenation, especially in patients with chronic lung disease.
  • Encourage smoking cessation to reduce further lung damage.
  • Enrol in pulmonary rehabilitation programs to improve exercise tolerance.
• Oxygen Therapy:
  • Long-term oxygen therapy (LTOT) is beneficial for patients with chronic hypoxia, aiming to maintain SpO₂ >90%.
• Pharmacological Management:
  • Diuretics such as furosemide or spironolactone to manage fluid overload and reduce oedema and ascites.
  • Inhaled bronchodilators and corticosteroids for underlying COPD or asthma.
  • Anticoagulation with warfarin or DOACs in cases of recurrent pulmonary embolism.
  • Vasodilators such as calcium channel blockers or phosphodiesterase inhibitors (e.g., sildenafil) may be considered for primary pulmonary hypertension.
• Treat Underlying Cause:
  • Manage chronic lung conditions such as COPD, interstitial lung disease, or obstructive sleep apnoea.
  • Address autoimmune conditions like rheumatoid arthritis with appropriate immunosuppressants.
• Advanced Interventions:
  • Pulmonary artery stenting or balloon angioplasty for patients with chronic thromboembolic pulmonary hypertension (CTEPH).
  • Heart-lung transplantation in carefully selected cases of end-stage disease refractory to other treatments.

Prognosis

• Prognosis depends on the underlying cause and the severity of right heart dysfunction.
• Early detection and management of the primary pulmonary condition can improve outcomes and delay the progression of cor pulmonale.
• Patients with advanced right heart failure and refractory hypoxia often have a poorer prognosis.

References

• Cor Pulmonale - NCBI Bookshelf
• European Respiratory Journal - Pulmonary hypertension and cor pulmonale
• NICE Guidelines on Chronic Obstructive Pulmonary Disease